BHEL Jhansi  

By the end of 5th five-year plan, it was envisaged by the planning commission that the demand for power transformer would rise in the coming years. Anticipating the country’s requirement BHEL decided to set up a new plant, which would manufacture power and other type of transformers in addition to the capacity available at BHEL, Bhopal. The Bhopal Plant was engaged in manufacturing of transformers of large rating and Jhansi unit would concentrate on power transformer upto 50 kVA, 132 kV Class and other transformers like Instrument Transformers, Traction Transformers for Railway etc.

This unit of Jhansi was established around 14 km from the city on the N.H. No. 26 on Jhansi Lalitpur road. It is called second generation plant of BHEL set up in 1974 at an estimated cost of Rs. 16.22 crores inclusive of Rs. 2.1 crores for township. Its foundation was laid by Late Mrs. Indira Gandhi the Prime Minister on 9th January 1974. The commercial production of the unit began in 1976-77 with an output of Rs. 53 Lacs since then there has been no looking back for BHEL, Jhansi.

This plant of BHEL is equipped with the most modern manufacturing processing and testing facilities for the manufacture of power, special transformer and Instrument transformers, Diesel shunting Locomotives and AC/DC Locomotives. The layout of the plant is such that it is well streamlined to enable smooth material flow from the raw material stages to finished goods. All the feeder bays have been laid perpendicular to main assembly bay and each feeder bay raw material smoothly gets converted to sub assemblies which after inspection are sent to main assembly bay.

The raw material that are produced for manufacture are used only after thorough material testing in the testing lab and with strict quality checks at various stages of productions. This unit of BHEL is basically engaged in the production and manufacture of transformers of various type and capacities with the growing competition in the transformer section, in 1985-88 it under took the re-powering of diesel, but it took a complete year for the manufacturing to began. In 1987-88, BHEL has progressed a step further in undertaking the production of AC Locomotives and subsequently it is manufacturing AC/DC Locomotives also.

SECTIONS OF BHEL JHANSI UNIT

BHEL has many departments, while production and Administrative departments are separate.

Broadly speaking BHEL, Jhansi has two production categories.

Transformer Loco

THE PRODUCT PROFILE OF BHEL JHANSI UNIT

Products Rating

1. Power Transformer Upto 220 kV Class 250 MVA

2. Special Transformer Upto 110 kV

3. ESP Transformer 100 kV, 1400 mA

4. Freight Loco Transformer 3900 to 5400 kVA & 6500 kVA (3 Phase)

5. ACEMU Transformer Upto 1000 kVA 25 kV(1 Phase)1385 kVA (3 Phase)

6. Dry Type Transformer Upto 3150 kVA

7. Bus-duct Upto 15.75 kV Generating Voltage.

8. Instrument Transformer VT & CT upto 220 kV Class.

9. Diesel electric Locomotives Upto 2600 HP.

10. AC/DC Locomotive 5000 HP.

11. Over Head Equipment cum Test Car.

GROWTH OF PRODUCTION AND MILESTONES

Year Milestone

1976-77 Start of Instrument Transformer production.

1977-78 Start of Traction Transformer and Power Transformer (upto 132 kV)

1978-79 Start of HFTT type freight Loco

1979-80 Commissioning of 2,500 kV DG Set (due to server Power Cuts).

1980-81 Start of ESP Transformer.

1981-82 Start of 220 kV Power Transformer.

1982-83 Achieved Break Even.

1983-84 Start of Bus-duct

1984-85 Start of dry type transformer.

1985-86 Re-powering of Diesel  Loco Started.

1986-87 Start of new Diesel Loco Manufacturing.

1987-88 Manufacturing facilities for AC Loco.

1988-89 Crossed 100 crore target.

1990-91 Successful design and manufacturing of 450 HP 3 Axel Diesel CCI

1991-92 Manufacturing of first 2600 HP Diesel for NTPC.

1992-93 Successful Design and Development of 5000 HP Thyristor control Locomotive.

1993-94 Unit has been awarded ISO-9001 certificate for quality systems.

1994-95 240 MVA Power Transformer Produced first time.

1995-96 AC/DC Locomotive first time in India.

1996-97 100th Loco Manufactured.

1997-98 250 MVA Transformer produced first time.

1998-99 Developed Over head equipment cum test Car.Exported one Diesel Loco to Malaysia.

Introduction

BHEL is the largest engineering and manufacturing enterprise in India in theenergyrelated/infrastructure sector, today. BHEL was established more than 40years ago,ushering in the indigenous Heavy Electrical Equipment industry in India - adreamthat has been more than realized with a well-recognized track record ofperformance.The company has been earning profits continuously since 1971-72 andpayingdividends since 1976-77.BHEL manufactures over 180 products under 30 major product groups andcaters tocore sectors of the Indian Economy viz., Power Generation & Transmission,Industry, Transportation, Telecommunication, Renewable Energy, etc. Thewidenetwork of BHEL's 14 manufacturing divisions, four Power Sector regionalcentres,over 100 project sites, eight service centres and 18 regional offices, enablestheCompany to promptly serve its customers and provide them with suitableproducts,systems and services -- efficiently and at competitive prices. The high level ofquality& reliability of its products is due to the emphasis on design, engineering andmanufacturing to international standards by acquiring and adapting some ofthe besttechnologies from leading companies in the world, together with technologiesdeveloped in its own R&D centresBHEL has•Installed equipment for over 90,000 MW of power generation -- for Utilities,Captive and Industrial users.•Supplied over 2,25,000 MVA transformer capacity and other equipmentoperating in Transmission & Distribution network up to 400 kV (AC & DC).

•Supplied over 25,000 Motors with Drive Control System to Power projects,Petrochemicals, Refineries, Steel, Aluminum, Fertilizer, Cement plants, etc.•Supplied Traction electrics and AC/DC locos to power over 12,000 kmsRailway network.•Supplied over one million Valves to Power Plants and other IndustriesBHEL's operations are organised around three business sectors, namelyPower,Industry - including Transmission, Transportation, Telecommunication &RenewableEnergy - and Overseas Business. This enables BHEL to have a strongcustomer orientation, to be sensitive to his needs and respond quickly to thechanges in the market.The fourteen manufacturing Divisions are located at•Bhopal(Madhya Pradesh)•Bharat Heavy Electrical Limited, Ranipur, Haridwar (Uttarakhand) [4]•Hyderabad (Andhra Pradesh)•Jhansi (Uttar Pradesh)•Tiruchirapalli(Tamil Nadu)•Ranipet (Tamil Nadu)•Bangalore (Karnataka)•Jagdishpur (Uttar Pradesh)•Rudrapur (Uttrakhand)•Goindwal (Punjab)Besides these manufacturing units there are four power sectors whichundertakeEPC contract from various customers. The Research and Development arm ofBHELis situated in Hyderabad and two repair shops are at HERP(Heavy EquipmentRepair Plant),Varanasi and EMRP(Electric machines repair plant) Mumbai.BHEL-HyderabadAs a member of the prestigious 'BHEL family', BHEL-Hyderabad has earned areputation as one of its most important manufacturing units, contributing itslion's

share in BHEL Corporation's overall business operations.The Hyderabad unit was set up in 1963 and started its operations withmanufactureof Turbo-generator sets and auxiliaries for 60 and 110 MW thermal utilitysets.Over the years it has increased its capacity range and diversified itsoperations tomany other areas. To day, a wide range of products are manufactured in thisunit,catering to the needs of variety of industries like Fertilisers & Chemicals,Petrochemicals & Refineries , Paper, sugar, steel , etc.BHEL-Hyderabad unit has collaborations with world renowned MNCs like M/SGeneral Electric, USA, M/S Siemens,Germany, M/S Nuovo Pignone, etc.Major products of this unit's manufacture include the following.•Gas turbines•Steam turbines•Compressors•Turbo generators•Heat Exchangers•Pumps•Pulverizers•Switch Gears•Gear Boxes•Oil Rigs•Project EngineeringSteam TurbinesOperationThe expansion of steam through numerous stages in the turbine causes theturbinerotor to rotate. Steam expands through impulse stage or reaction stage.•Impulse steam turbine stage consists as usual from stator which known asthenozzle and rotor or moving blades•

Impulse turbine are characterized by the that most or all enthalpy and hencepressure drop occurs in the nozzle.•The rotor blades can be recognized by their shape, which is symmetrical andhave entrance and exit angles around 20o. They are short and have constantcross sectionsAt BHEL-Hyderabad, compounded turbines are made as they are the mostused byplants•Compounded steam turbine means multistage turbine.•Compounding is needed when large enthalpy drop is available.•Since optimum blade speed is related to the exit nozzle speed. It will behigher as the enthalpy drop is higher.•The blade speed is limited by the centrifugal force as well as needs ofbulky reduction gear•Compounding can be achieved either by velocity compounded turbine orpressure compounded turbine.Velocity Compounded Turbine•It is composed of one stage of nozzles, as the single stage turbine,followed by two rows of moving blades instead of one.•These two rows are separated by one row of fixed blades which has thefunction of redirecting the steam leaving the first row of the moving bladesto the second row of moving blades.Pressure Compounded Impulse Turbine•Pressure compounding impulse turbine is a multistage impulse turbinewhere expansion in the fixed blades (nozzles) is achieved equally amongthe stages.•Accordingly the inlet steam velocity to each stage is essentially equal, dueto equal drop in enthalpy.•This equal enthalpy drop does not mean equal pressure dropThe Manufacture and Parts

Casing

The typical casing for an Elliott turbine consists of a cast high-pressure steamchest,an intermediate barrel section, and a separate exhaust casing. The barrelsection isgenerally integral with the steam chest so that the vertical bolting joint is atone of thelatter stages where internal pressures are very much reduced. The steamend,exhaust casing, nozzle ring, reversing blades and diaphragms are all split onthehorizontal center line which allows for easy removal of the upper half of theturbinefor internal inspection.The diaphragms are machined on the outside diameter and assembled intogroovesaccurately machined in the casing. Cap screws, secured by locking, fastenthenozzle ring to the steam chest, while the diaphragm halves are locked inposition bystops located at the horizontal split in the casing.Steam chest passages, nozzle block partitions and the valve openingsequence areall carefully designed to ensure even and rapid heating of the casing aftersteam isfirst admitted to the turbine. The high-pressure end of the turbine issupported by thesteam end bearing housing which is flexibly mounted to allow for axialexpansioncaused by temperature changes. The exhaust casing is centerline supportedonpedestals that maintain perfect unit alignment while permitting lateralexpansion.Covers on both the steam end and exhaust end bearing housings and sealhousings

may be lifted independently of the main casing to provide ready access tosuch itemsas the bearings, control components and seals.

Rotors

Rotors are precisely machined from solid alloy steel forgings. An integrallyforgedrotor provides increased reliability particularly for high speed applications.The complete rotor assembly is dynamically balanced at operating speed andoverspeed tested in a vacuum bunker to ensure safety in operation. Highspeedbalancing can also reduce residual stresses and the effects of blade seating.Elliottalso offers remote monitoring of the high speed balance testing, allowingcustomersto witness the testing from their offices or at any other location.

Blades

Blades are milled from stainless steel stock purchased within strictspecifications forproper strength, damping and corrosion resistant properties. Disk profiles aredesigned to minimize centrifugal stresses, thermal gradient and bladeloading at thedisk rims. The blades have various shapes to achieve maximum performanceandwithstand any mechanical stresses.

Stationary Components

Nozzle rings and diaphragms are specifically designed and fabricated tohandle thepressure, temperature and volume of the steam, the size of the turbine andtherequired pressure drop across the stage. The nozzles used in the first stagenozzlering are cut from stainless steel. Steam passages are then precision milledinto thesenozzle blocks before they are welded together to form the nozzle ring.The nozzles in the intermediate pressure stages are formed from profiledstainlesssteel nozzle sections and inner and outer bands. These are then welded to acircularcenter section and to an outer ring then precision machined.The low-pressure diaphragms in condensing turbines are made by casting thestainless nozzle sections directly into high-strength cast iron. This designincludes amoisture catching provision around the circumference which collects releasedmoisture and removes it from the steam passage. Additional features such aswindage shields and inter-stage drains are used as required by stageconditions tominimize erosion. All diaphragms are horizontally split for easy removal andalignment adjustment.Labyrinth seals are utilized as end gland seals and also interstage seals.Stationarylabyrinth seals are standard for all multistage turbines and grooves aremachined onthe rotating part to improve the sealing effect. The leakage steam from the

outerglands is generally condensed by the gland condenser. Some leakage steamfromthe intermediate section of the steam end gland seals can be withdrawn andutilizedby re-injecting it into the low-pressure stage or low- pressure steam line.Replaceable journal bearings are steel-backed and babbitt-lined with fiveshoetiltingpad design. Thrust bearings are double-acting and self-equalizing. Centerpivots aretypically used to make assembly easier and provide maximum protection ifreversefor high oil temperature applications.

Turbo Generators

The turbo-generator is common-shaft excitation AC synchronous generatorwith 3phases, 2 poles or with 3 phases, 4 poles.BHEL-Hyderabad makes turbo generators that have the brushless excitationmechanism which has been explained in the NTPC report.BHEL presently has manufactured Turbo-Generators of ratings upto 560 MWand isin the process of going upto 660 MW. It has also the capability to take up themanufacture of ratings upto 1000 MW suitable for thermal power generation,gasbased and combined cycle power generation as-well-as for diverse industrialapplications like Paper, Sugar, Cement, Petrochemical, Fertilizers, RayonIndustries,etc.

The Manufacture of the Turbo GeneratorStator

The stator is assembled as six parts. It is made up of steel with 4.5% of silica.Silicadecreases hysteresis loss. The sheets are cut at 30 degree angles.The sheets then are punched with man drill holes, support rod slots and slotsfor theconductors. This process is called notching and the cutting part as shearing.The sheets are then varnished after blanking or smoothening of the surface.This isto increase the insulation.A bunch of these sheets are stacked together and compressed onto eachother so that air gaps are eliminated. These stacks are then assembled with asmall air gap differentiating each stack. This ventilates the machine andkeeps it cool.After the assembly of the stator shell, the inside of the slots are varnished.The sheets of the core are varnished with xylor, at a temperature of 30-400degreesCelsius. It is heated, coated then cooled.After the core is assembled , the winding is placed in the stator. The windingtypedepends upon the power required and the current required to be produced.The core and the winding are separated by an insulation called HGL. Thispreventsthe shorting of the core and winding

The winding in the front and back are also separated by this material andthey arejoined as per the winding required (lap or wave) using glass-o-flex, a pinkribbon likematerial.The windings are insulated. These windings are then painted to obtain a thestator,where the power is generated. The windings are always inserted from theexciterend, one is clockwise and the other anti-clockwise

The Rotor

The rotor is carved out with the slots into a cylindrical shape from a largeblock ofmetal using Lathe heavy machines.The rotor consists of 2 ends –•The turbine coupling end•The exciter endThe turbine end has a coupling shaft which is circular in shape and has slots.The exciter end has an input lead and an output lead which are used to givethe rotorDC input for the excitation of the rotating field.The ends of each rotor consist of bearings. These bearings are placed so as tosupport the shaft. The bearing consists of oil which is used to support a thinfilm overthe surface. This lubricates and decreases friction and losses. The bearinghas topend and bottom end and is stationary. The top end is used to supply the oil.After the construction, the w inding is fitted into the slotsThe slots and windings are separated by HGL or hard glass lamination whichinsulates the core from the cable. The rotor is constructed so as to obtainbrushlessexcitation.The complete rotor along with the excitation mechanism is mounted on the

shaft and is balanced for synchronous speed. For better balancing weightremoval is done as that is a better option to adding weight to the system.The rotor ends are provided with induction motor fans which are used forcooling ofthe rotor winding. The winding is mad eup of 99.99 % copper.

Cooling of the Alternator

The machine needs to be cooled to avoid damage and for greater life.Heatingcauses insulation failure. Hence, cooling is a very important factor that needsto betaken care of.For cooling, the stator and rotor are provided with a ventilation to cool itdown. Airgaps are provided throughout the machine. But for very high power machinesnaturalWith this interrupting principle it is possible, during high-currentinterruptions, toincrease by about 30% the tripping energy delivered by the operatingmechanismand to maintain the opening speed independently of the current. It isobviously bettersuited to circuit-breakers with high breaking currents such as Generatorcircuitbreakers.cooling is insufficient so a cooling system is provided. For collection of hotair, alarge chamber is provided. This air is cooled and recycled into the generator.Therotor of the alternator consists of fans powered by induction motors. They

suck in theair and push it through to the cooling chamber.Another method is also used which is called hydrogen cooling. Hydrogen actsas a coolant and the chamber is shut completely is filled with hydrogen.Hydrogen cools itself.The chamber is emptied each time the machine is stopped.

Circuit –Breakers

Current interruption in a high-voltage circuit-breaker is obtained byseparating twocontacts in a medium, such as SF6, having excellent dielectric and arcquenchingproperties. After contact separation, current is carried through an arc and isinterrupted when this arc is cooled by a gas blast of sufficient intensity.Gas blast applied on the arc must be able to cool it rapidly so that gastemperaturebetween the contacts is reduced from 20,000 K to less than 2000 K in a fewhundredmicroseconds, so that it is able to withstand the transient recovery voltagethat isapplied across the contacts after current interruption. Sulphur hexafluoride isgenerally used in present high-voltage circuit-breakers (of rated voltagehigher than52 kV)In arc assisted opening interruption principle arc energy is used, on the onehand togenerate the blast by thermal expansion and, on the other hand, toaccelerate themoving part of the circuit breaker when interrupting high currents. Theoverpressure

produced by the arc energy downstream of the interruption zone is appliedon anauxiliary piston linked with the moving part. The resulting force acceleratesthemoving part, thus increasing the energy available for tripping.